Historic U.S. Documents Online

American Memory Collection (Library of Congress)

Charters of Freedom (National Archives) - Includes the Declaration of Independence, the Constitution, and the Bill of Rights

Constitution of the United States (Emory) - Includes breakdown by topic within the U.S. Constitution

Constitution of the United States (GPO) - Includes U.S. Supreme Court Decisions concerning the U.S. Constitution (Beginning to the Year 2000)

Federalist Papers (Thomas)

Foreign Relations of the United States - Selected Documents (Avalon Project)

Foreign Relations of the United States - Online Volumes (Department of State)

Historic Documents (University of Michigan)

Historical Publications of the United States Commission on Civil Rights - through the  University of Maryland Thurgood Marshall Law Library portal

National Archives (homepage)

Measuring America: The Decennial Censuses from 1790 to 2000 [pdf format]

Peoples Vote - 100 Milestone Documents from NARA - Most Influential Documents in U.S. History - The People’s Vote, co-sponsored by the National Archives and Records Administration, National History Day, and U.S. News & World Report, invited Americans of all ages and educational backgrounds to vote for 10 of 100 milestone documents drawn mainly from the holdings of the National Archives. The documents chronicle United States history from 1776 to 1965. Learn more about the vote. 100 Milestone Documents in chronological order - click on this link

Primary Documents in American History (Library of Congress)

Public Papers of the Presidents 1992-2001

Words and Deeds in American History (Library of Congress)